scholarly journals Thermal Cracking in Westerly Granite Monitored Using Direct Wave Velocity, Coda Wave Interferometry, and Acoustic Emissions

2018 ◽  
Vol 123 (3) ◽  
pp. 2246-2261 ◽  
Author(s):  
L. Griffiths ◽  
O. Lengliné ◽  
M. J. Heap ◽  
P. Baud ◽  
J. Schmittbuhl
Keyword(s):  
Wave Velocity ◽  
Acoustic Emissions ◽  
Thermal Cracking ◽  
Coda Wave ◽  
Direct Wave ◽  
Coda Wave Interferometry

Time lapse monitoring of acoustic emissions with Coda Wave interferometry

2002 ◽  
Author(s):  
Alexandre Gre⁁t ◽  
Roel Snieder ◽  
John Scales ◽  
Mike Batzle
Keyword(s):  
Acoustic Emissions ◽  
Time Lapse ◽  
Coda Wave ◽  
Coda Wave Interferometry

Multiplet Based Time Lapse Velocity Changes Prior to the 2018 Eruption of Sierra Negra Volcano, Galapagos Island Observed with Coda Wave Interferometry

2020 ◽  
Author(s):  
Mariantonietta Longobardi ◽  
James Grannel ◽  
Christopher Bean ◽  
Andrew Bell ◽  
Mario Ruiz
Keyword(s):  
Wave Velocity ◽  
Seismic Wave ◽  
Seismic Velocity ◽  
Time Lapse ◽  
Coda Wave ◽  
Seismic Wave Velocity ◽  
Galapagos Island ◽  
Velocity Changes ◽  
Coda Wave Interferometry ◽  
Sierra Negra Volcano

<p align="justify"><span>Changes in external stress state and fluid content alter the mechanical properties of an geological media. </span><span>Variations in seismic wave velocity can be used as proxies for changes in stress the onset of mechanical demage and/or possible fluid ingression. Temporal variations in seismic wave velocity have previously been monitored and observed prior to volcanic eruptions. In the absence of additional constraints related to stress or fluid changes on the volcano, these pre-eruptive changes are difficult to interpret and hence the causes of them are often not well understood. </span><span>In this study, Coda Wave Interferometry (CWI) is used to measure time-lapse changes in seismic velocity on seismic multiplets (repeating similar earthquakes). In particular, we focus our analysis on using this technique to calculate the velocity changes on the data recorded prior to the 2018 eruption of Sierra Negra volcano, Galapagos Island.</span> <span>On 26th June 2018 at 09:15 UTC, a magnitude 5.3 earthquake occurred near the south-west caldera rim and an intense seismic swarm started around 17:15 UTC. Seismic tremor dominated at about 19:45 UTC, which marked the onset of the eruption. </span><span>A very large seismicity sequence preceded the eruption. The pricise relationship between the magnitude 5.3 event and the eruption is not fully constraind. Here we search for multiplets in order to achieve high time resolution velocity change information in the hours between the large earthquake and the eruption. </span><span>Our aim is to understand whether changes in seismic velocity measured with CWI on multiplets method provide new insight into the physical processes related to the eruption.</span></p><p align="justify"><br><br></p>

scholarly journals The installation of embedded ultrasonic transducers inside a bridge to monitor temperature and load influence using coda wave interferometry technique

2021 ◽  
pp. 147592172110144
Author(s):  
Xin Wang ◽  
Ernst Niederleithinger ◽  
Iris Hindersmann
Keyword(s):  
Wave Velocity ◽  
Ultrasonic Transducer ◽  
Load Test ◽  
Ultrasonic Transducers ◽  
Coda Wave ◽  
Velocity Variation ◽  
Small Scale ◽  
Load Effect ◽  
Structural Health ◽  
Coda Wave Interferometry

This article presents a unique method of installing a special type of embedded ultrasonic transducers inside a 36-m-long section of an old bridge in Germany. A small-scale load test was carried out by a 16 ton truck to study the temperature and load influence on the bridge, as well as the performance of the embedded transducers. Ultrasonic coda wave interferometry technique, which has high sensitivity in detecting subtle changes in a heterogeneous medium, was used for the data evaluation and interpretation. The separation of two main influence factors (load effect and temperature variation) is studied, and future applications of wave velocity variation rate [Formula: see text] for structural health condition estimation are discussed. As a preliminary research stage, the installation method and the performance of the ultrasonic transducer are recognized. Load- and temperature-induced weak wave velocity variations are successfully detected with a high resolution of 10−4%. The feasibility of the whole system for long-term structural health monitoring is considered, and further research is planned.

Monitoring medium changes in an intraplate setting with coda wave interferometry

2013 ◽  
Author(s):  
Virginie D'Hour ◽  
Aderson F. do Nascimento ◽  
Heleno C. de Lima Neto ◽  
Joaquim M. Ferreira ◽  
Martin Schimmel
Keyword(s):  
Coda Wave ◽  
Coda Wave Interferometry

scholarly journals Sensitivity of Ultrasonic Coda Wave Interferometry to Material Damage—Observations from a Virtual Concrete Lab

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4033
Author(s):  
Claudia Finger ◽  
Leslie Saydak ◽  
Giao Vu ◽  
Jithender J. Timothy ◽  
Günther Meschke ◽  
...  
Keyword(s):  
Elastic Moduli ◽  
Concrete Specimen ◽  
Coda Wave ◽  
Velocity Change ◽  
Damage Scenarios ◽  
Different Types ◽  
Source Signal ◽  
The Impact ◽  
Structural Scale ◽  
Coda Wave Interferometry

Ultrasonic measurements are used in civil engineering for structural health monitoring of concrete infrastructures. The late portion of the ultrasonic wavefield, the coda, is sensitive to small changes in the elastic moduli of the material. Coda Wave Interferometry (CWI) correlates these small changes in the coda with the wavefield recorded in intact, or unperturbed, concrete specimen to reveal the amount of velocity change that occurred. CWI has the potential to detect localized damages and global velocity reductions alike. In this study, the sensitivity of CWI to different types of concrete mesostructures and their damage levels is investigated numerically. Realistic numerical concrete models of concrete specimen are generated, and damage evolution is simulated using the discrete element method. In the virtual concrete lab, the simulated ultrasonic wavefield is propagated from one transducer using a realistic source signal and recorded at a second transducer. Different damage scenarios reveal a different slope in the decorrelation of waveforms with the observed reduction in velocities in the material. Finally, the impact and possible generalizations of the findings are discussed, and recommendations are given for a potential application of CWI in concrete at structural scale.

Monitoring cleaning cycles of fouled ducts using ultrasonic coda wave interferometry (CWI)

Ultrasonics ◽  
2019 ◽  
Vol 96 ◽  
pp. 253-260 ◽  
Author(s):  
B. Chen ◽  
D. Callens ◽  
P. Campistron ◽  
E. Moulin ◽  
P. Debreyne ◽  
...  
Keyword(s):  
Coda Wave ◽  
Coda Wave Interferometry

scholarly journals Toward Robust and Routine Determination of Mw for Small Earthquakes: Application to the 2020 Mw 5.7 Magna, Utah, Seismic Sequence

2021 ◽  
Author(s):  
James Holt ◽  
Katherine M. Whidden ◽  
Keith D. Koper ◽  
Kristine L. Pankow ◽  
Kevin Mayeda ◽  
...  
Keyword(s):  
Spectral Methods ◽  
Moment Tensor ◽  
Coda Wave ◽  
Strongly Correlated ◽  
Seismic Sequence ◽  
Wave Method ◽  
Direct Wave ◽  
Main Requirement ◽  
Relationship Of

Abstract To better characterize seismic hazard, particularly, for induced seismicity, there is an increasing interest in methods to estimate moment magnitude (Mw) for small earthquakes. Mw is generally preferred over other magnitude types, but, it is difficult to estimate Mw for earthquakes with local magnitude (ML) <3–3.5, using conventional moment tensor (MT) inversion. The 2020 Mww 5.7 Magna, Utah, seismic sequence provides an opportunity to illustrate and evaluate the value of spectral methods for this purpose. Starting with a high-quality seismic catalog of 2103 earthquakes (ML<5.6), we estimate Mw using two independent spectral methods—one based on direct waves, yielding Mw,direct, and the other based on coda waves, yielding Mw,coda. For the direct-wave method, we present a non-parametric (NP) inversion scheme that solves for apparent geometrical spreading, G(R), and site effects (S), similar to other NP procedures that have been used to calibrate regional ML scales. The NP inversion is constrained using Mws derived from MTs for nine events in the Magna sequence. We recover statistically robust and physically reasonable G(R) and S and compute Mw,direct for 635 Magna earthquakes down to ML 0.7. For the coda-wave method, we consider two separate calibration schemes involving previous MT solutions and compute Mw,coda for 311 earthquakes down to ML 1.0. For 280 of the events that were processed with both methods—Mw,direct and Mw,coda—are strongly correlated (r = 0.98), with a mean difference of only 0.05. We compare Mw,direct and Mw,coda with ML and find reasonably good agreement for ML<3.6 with the theoretically predicted relationship of Mw=(2/3)ML+C, in which C is a regional constant. Our results imply that seismic network operators can use spectral-based Mw estimates to replace ML estimates for events with ML≥1.0, and possibly smaller. The main requirement is the existence of a small number of MT solutions for calibration purposes.

Sign in / Sign up

Export Citation Format

Share Document